The effects of a steel installation base on the proposed microstrip patch antenna are investigated. The models of the antenna with different surroundings are established in Ansoft HFSS software. The variations in antenna performances are compared in simulation and measurement, respectively. And Good agreements are achieved between the measured and simulated results. It is found that the resonant frequency is shifted upward by about 60MHz with the introduction of the steel base, while the matching level is decreased. Meanwhile, the VSWR 2:1 bandwidth is reduced by about 80MHz. The results indicate that the steel base has great influences on the antenna characteristics, and the simulation work provides powerful guidance for the antenna design.