Sparse constrained deconvolution of seismic data is built on the assumption that the reflectivity is composed by a series of sparse pulses.Sparse constraint can be applied to reflectivity in deconvolution,avoiding the two hypotheses that the wavelet is minimum phase and the reflectivity is white noise.L0 norm is the most suitable measurement of data sparseness.Therefore,we bring L0 norm sparse constraint in seismic data deconvolution.Through applying L0 norm constraint to reflectivity,the optimization objective function of seismic data deconvolution is built.Iterative hard thresholding method is used to calculate the function and sparsely distributed reflectivity is obtained.The validity of L0 norm sparse constraint deconvolution is proved by the comparison with Cauchy criterion constraint and L1 norm constraint in synthetic model tests.