Microstrip antenna is widely used in telemetry system due to its small size, easy conformal and suitable for metal environment. Aiming at the narrow bandwidth of traditional microstrip telemetry antenna, a design to expand bandwidth by slotting on antenna patch and floor is proposed, simulation and test verification are carried out and their results are consistent with each other. The HFSS simulation results show that the relative impedance bandwidth(S11<-10dB) of the antenna is 5.6%(2.409~2.545GHz) which basically covers the ISM frequency band by slotting at appropriate positions and the highest gain can reach 4 dBi. Test results show that its relative impedance bandwidth is 6%(2.41~2.56GHz) and the transmission coefficient of S21 is about -22 dB when the distance between two antennas is kept at 10 mm, which meets the requirements of the telemetry system.