Abstract: This paper studied the precise design of Microstrip Narrow Band Pass Filter(MNBPF) ,summarized a set of equations according to engineering experience,gave the corrected equation to calculate the length of resonator,compiled the CAD program,gave the data of two practical MNBPFs and measured results.From this,it is conclude that MNBPF is a good filter for spaceborne Telemetry,Tracking and Command(TT&C)system because it has the virtues of small volume,light weight,high reliability and need no adjustment.