Habitat drying caused by global warming will raise a challenge for anuran larvae living in water. We investigated the phenotypic response to six different patterns of water level change in Bufo gargarizans and Duttaphrynus melanosticus tadpoles under laboratory conditions. The aim of this study was to examine the heritable basis and environmental proximate causes of phenotypic plasticity of these two species tadpoles. The results showed that all the six water level treatments had no significant effect on the early development Gosner stage (GS), head width (HW), or body mass (BM) of B. gargarizans tadpoles on the 14th day, but there was a significant effect on their snout-vent length (SVL). The SVL of B. gargarizans tadpoles raised in decreasing water levels were the longest, while the ones raised in constant low water levels had the shortest SVL than the remaining groups. Conversely, the six water level treatments had respectively significant effects on the GS, SVL, HW and BM of D. melanosticus tadpoles on the same day, respectively. Firstly, those tadpoles raised in constant high water level developed most fast, while the ones raised in constant low water level developed most slowly. Secondly, the tadpoles raised in decreasing water level had greater SVL, while the ones raised in constant low, fast fluctuation and slow fluctuation water levels had smaller SVL than the remaining groups. Thirdly, HW of the tadpoles raised in constant low water levels was the narrowest, followed by the ones raised in increasing water levels, the others raised in the remaining water level groups had the biggest HW. Lastly, BM of tadpoles in constant low water levels was the smallest, while the ones raised in constant high water level had heavier BM than the remaining groups. The water level treatments had no significant effect on the time of metamorphosis and body size at metamorphosis including SVL, HW, and BM in B. gargarizan. However, there were significant effects of the water level changes on the time of metamorphosis and body size at metamorphosis including SVL and BM, except for HW, in D. melanosticus. Tadpoles raised in the constant low water levels had protracted metamorphosis, whereas the tadpoles raised under the constant high water levels had shortened metamorphosis. SVL at metamorphosis of D. melanosticus in the constant high water levels was the largest, while the ones raised in constant low and rapidly fluctuating water levels were the shortest. BM at metamorphosis of D. melanosticus raised in the increasing and rapidly fluctuating water levels were the biggest, while the ones raised in the constant low water levels were the smallest. Our results suggest that there are significant interspecific differences in the phenotypic plasticity respond to desiccation risks between B. gargarizans and D. melanosticus tadpoles: the former was weaker than the latter. Winter-breeder B. gargarizans tadpoles experienced habitat drying more frequently, while spring-breeder D. melanosticus tadpoles experienced habitat drying rarely. This showed the interspecific differences and hereditary of the phenotypic plasticity. During the early development of the two toad tadpoles, the common phenotypic variations in their SVL were associated with lack of genetic basis of environmental proximate causes. The response to constant low or decreasing water level in D. melanosticus tadpoles was negative (deceleration of differentiation), and the response degree was directly related to the strength of the environmental signals.