The invention relates to a combined amending method and a combined amending system for residual time frequency offset in an OFDM (orthogonal frequency division multiplexing) system. The combined amending method comprises the steps of 1, performing OFDM demodulating on a receiving end and removing the demodulating information carried by subcarriers to obtain the symbol phase rotation caused only by the residual time frequency offset; 2, setting an optimizing principle and selecting plural positive and negative frequency points of an OFDM symbol to form a positive-negative frequency point set; 3, establishing the relation between the residual time offset mark position and carrier frequency offset estimating value to obtain the residual frequency offset estimating value according to the relation between the phase sums of positive and negative frequency points in the set, or establishing the relation between the residual frequency offset mark position and the sampling frequency offset estimating value to obtain the residual time offset estimating value; and 4, adopting the frequency offset estimating value and the time offset estimating value to perform combined amending on the channel estimating value to obtain the updated channel estimating value to finish the amending. The combined amending method has the advantages of improving the stability and accuracy of amending, reducing the effect of single estimating error, effectively preventing error accumulating and improving the system property.