Abstract: To simplify engineering implementation and take full advantage of adjacent reference signals to estimate the channel response at data sub-carriers exactly in the long term evolution system (LTE), an interpolation estimation algorithm based on adaptive matrix-spline interpolation is proposed. According to mathematical theory of spline interpolation, an expression of matrix-spline interpolation for downlink physical channel is deduced. The proposed algorithm is optimized by decomposing and overlapping the interpolation region, and the decomposition length is adaptively selected by correlation bandwidth. Simulation results indicate that in the condition of low engineering realization complexity, the proposed interpolation algorithm is superior to common polynomial interpolations, and can track the change of the channel state dynamically.