The combustion indicator diagrams were measured on a single cylinder diesel engine fueled with different blended fuels of diesel and methanol. The combustion cyclic variation of blended fuel was studied under different conditions, which analyzed the evaluation parameters of cyclic variation such as the maximum pressure rise rate coefficient COV(dp/dφ)max the mean indicated pressure coefficient COVpmi, the maximum combustion pressure coefficient COVpmax and the standard error of its corresponding crank angle SDφpmax . The results show that COV(dp/dφ)max and COVpmi increase with the increase of methanol mixing ratio.Compared with biodiesel, the changes of cyclic variation coefficients are smaller when the mixing ratios are 10% and 20%.When the mixing ratio of methanol increases to 30%, the COV(dp/dφ)max increases by 6.2%, COVpmi increases by 24.2%, and  COVpmax increases by 8.4%. For the constant mixing ratio, COV(dp/dφ)max decreases and COVpmi and COVpmax first decrease and then increase with the increase of speed. With the increase of load, the cyclic variation coefficients of all pressure parameters decrease, but the corresponding standard error of maximum combustion pressure slightly increases.