Exploring diurnal variations and controlling factors of stem maintenance respiration (R_M) is important for understanding tree carbon metabolism and its response to environmental changes and developing forest carbon cycling models. In this study, we used an infrared gas analyzer (LI-6400 IRGA) to in situ measure the diurnal dynamics in R_M for four temperate coniferous tree species in northeastern China. The tree species included three evergreen (i.e., Korean pine (Pinus koraiensis), Korean spruce (Picea koraiensis), and Mongolian pine (Pinus sylvestris var. mongolica)) and one deciduous (Dahurian larch (Larix gmelinii)) species. Twelve replicate trees with various diameters at breast height (DBH) were randomly sampled for each tree species. The R_M for each sampled tree was measured every 1.5 h around the clock before the growth started in spring (late April-early May) and after the growth ceased in autumn (October-November). A polyvinyl chloride (PVC) collar was installed at breast height of the stem on the northern direction of each sampled tree for measuring the R_M. Stem temperature at the 1 cm depth beneath the bark (T_W) was simultaneously measured 3 cm above the collar with a digital thermometer. The results showed that the diurnal variation in R_M largely followed the change in T_W for all the tree species in both autumn and spring with a "unimodal" or "bimodal" pattern, but the daily maximum value, occurring time and amplitude of R_M varied with tree species and seasons. T_W explained more than 50% variations in R_M for all the species except for Mongolian pine in spring, which suggested that T_W be a key environmental factor regulating the R_M. However, R_M lagged behind T_W by 1.5 h (3 h for Mongolian pine in spring). Normalized R_M at 10 ℃ (R₁₀) was significantly lower in autumn than that in spring for each species, ranging from 0.54 μmol CO₂ m^-2 s^-1 for Dahurian larch to 0.78 μmol CO₂ m^-2 s^-1 for Korean spruce in autumn and from 0.87 μmol CO₂ m^-2 s^-1 for Korean pine to 1.10 μmol CO₂ m^-2 s^-1 for Mongolian pine in spring, respectively. The mean R₁₀ was about 40% lower in autumn than in spring. There was no significant difference in Q₁₀ value of R_M between autumn and spring for each species (P > 0.05), ranging between 1.52 for Mongolian pine and 1.82 for Korean spruce. The R₁₀ was significantly positively correlated with DBH for all the species in both seasons, while the Q₁₀ was negatively with DBH (all P < 0.05). This suggested that DBH can be used as a proxy for predicting the R_M for these temperate tree species.