With the development of vehicle to everything (V2X), many technical challenges have emerged, among which, the collision avoidance of user equipment (UE) resource selection stands out. Resource reservation and sensing before transmitting are proposed to be effective enhancements. Reference Signal Received Power (RSRP) measurement is adopted in sensing procedure to exclude occupied resources. Theoretically, the physical sidelink shared channel (PSSCH) RSRP measurement accuracy affects the selection result of sensing procedure, which further affects the performance of collision avoidance. Thus, in this paper, the accuracy of PSSCH-RSRP is analyzed. The Least-Square (LS) channel estimation algorithm is used in the measurement. Various scenarios are considered in our test, i.e., Additive White Gaussian Noise (AWGN), Extended Vehicular A model (EVA), Extended Typical Urban model (ETU). The measurement also takes different Signal-Noise Ratio (SNR) and measurement period into consideration.