The compensation method for the error of diamond tool’s cutting edge is a bottle-neck technology to hinder the high accuracy aspheric surface’s directly formation after single diamond turning. Especially to the big relative aperture aspheric, influence is bigger. Traditional compensation was done according to the measurement result from profile meter, which took long measurement time and caused low processing efficiency. A new compensation method was firstly put forward in the article, in which the correction of the error of diamond tool’s cutting edge was done according to measurement result from digital interferometer. First, detailed theoretical calculation related with compensation method was deduced. Then, the effect after compensation was simulated by computer. Finally, φ50 mm , radius 50 mm, work piece with big relative aperture finished its diamond turning and new correction turning under Nanotech 250. Testing surface achieved high shape accuracy PV=86 nm and RMS=7 nm, which approved of the new compensation method agreeing with predictive analysis, high accuracy and fast speed of error convergence.