Abstract: According to Gardener algorithm based on 16 quadrature am plitude modulation(16QAM) communication system, an improved interpolation structure is proposed .It reduces the systematic errors caused by spectrum aliasing and improves the accuracy of the output of the filter. Timing error detection method is modified to achieve four level modulation signal symbol error and hardware implementation complexity is low. Simulation and practical test show that the algorithm has high robustness and effectiveness in low SNR and high symbol deviation.