In recent years, microplastic contamination of agricultural land has become serious, and soil has become a sink for microplastics, posing great risks to soil health and crop safety. In order to investigate the influence of microplastics on the soilplant system, a rice cultivation experiment was conducted with different treatments of low density polyethylene (LDPE) with different mass fractions (0, 0.5%, 1.5%) and particle sizes (150μm, 500μm) to investigate the effects of LDPE on the soil nutrient content, rice growth and physiological characteristics. The results showed that microplastics could increase the total organic carbon (TOC) content of the surface (0~10cm) and middle (10~20cm) soil in the first and middle stages of rice growth (greening, tillering and nodulation) by 6.06%~43.24%, and decrease the TOC content in the late stage (tasseling and yellow ripening) by 6.10%~20.53%, and the trend of the deep soil (20~30cm) was the opposite. Meanwhile, it could significantly reduce the total nitrogen (TN) 5.23%~53.73% and total phosphorus (TP) 2.01%~24.66% in different soil layers. Microplastics were able to promote rice plant height by 3.42%~18.32% in the early stage, inhibit rice plant height by 1.90%~13.96% in the middle and late stage, and reduce rice yield by 7.80%~24.83%. Microplastics were able to significantly reduce rice net photosynthetic rate (Pn) by 6.36%~40.46%, stomatal conductance (Gs) by 3.40%~67.36%, and intercellular CO2 concentration (Ci) by 3.66%~21.86%, and significantly increase saturated vapor pressure difference (VPD) by 14.16%~109.60%, and the promoting effect of VPD on water vapor diffusion was much greater than that on the Gs. The inhibitory effect of VPD on water vapor diffusion was much greater than the inhibitory effect on Gs, which ultimately led to a significant increase in transpiration rate (Tr) by 10.79%~82.37%, and, at the same time, a decrease in chlorophyll a content by 0.27%~3.48%, chlorophyll b content by 0.36%~3.92%, and total chlorophyll content by 0.59%~3.47%. The research results can provide data support and scientific basis for the effect of microplastics on soil health and rice growth stress.