According to the functional requirement of the portable underground pipe water leakage detector, a real-time signal acquisition and transporting system based on MS320VC5416 DSP is designed. The realization of the FIR digital filter algorithm on DSP is proposed and the key technologies of filter order、filter algorithm、sample frequency 、clock frequency are analyzed. Testing on-the-spot and simulation analysis show that the real-time, stability and antinoise capabilities of the system meet with the design requirements.