In heterogeneous habitats of karst areas, the combined effects of soil moisture content, plants' living space and nutrient status may influence the physiological function and growth of plants. In this research, L.perenne was taken as the research material to explore the adaptation of plants to heterogeneous habitats under three scenarios of precipitation (control group: W₀, moderate drought: W₁, and severe drought: W₂) by simulating two microhabitats, namely homogeneous habitat (S-S: shallow-shallow soil) and heterogeneous habitat (S-D: shallow-deep soil). We mainly investigated the following questions: Whether plants in heterogeneous habitats actively improve their adaptation to heterogeneous habitats by actively seeking more resources such as water in deep soil? Whether the rainfall regulate the adaptation strategies? The main findings are as follows. 1) Only in the scenario of severe drought (W₂), plant height, tiller number, above/below-ground biomass and shoot/root mass fraction of L.perenne in heterogeneous habitat were significantly higher than those in homogeneous habitat. There was no significant difference between the two habitats in scenario W₀ and scenario W₁. 2) In scenario W₀, root biomass and root tissue density of L. perenne in the shallow area of heterogeneous habitat were less than those in deep area, and the specific root length and specific root area were larger than those in deep area. With the decrease of precipitation, the proportion of root biomass in shallow area to the whole plant root biomass showed a tendency of declining at the beginning and rising up later. The specific root length and specific root area of the deep area increased gradually, and the root tissue density decreased gradually. The above results indicate that L.perenne showed a stronger ability to resist drought stress in the heterogeneous habitat, and this kind of advantage became more apparent as the drought degree went aggravating. L.perenne in heterogeneous habitat distributed limited biomass to the deep area, at the same time, the root tissue density of the root system in the deep area increased, so that the root system could proliferate in patches with good growth environment, where the plant could obtain a large amount of water and nutrients; while in shallow area, L.perenne made full use of limited resources and develops root systems by increasing specific root length and specific root area, and reducing root tissue density. Water and nutrients in shallow area were utilized as much as possible. With the increase of drought degree, the biomass in deep soil increased to some extent on the premise of maintaining normal physiological activities in the shallow area. When the root length and root area of shallow area increased to a certain limit, plants would respond to drought stress by increasing the specific root length and specific root area of root in deep area and reducing the root tissue density gradually.