With the input of the artificial multi-point and multi-direction seismic motion

the formula on safety factor of slope under earthquake is deduced based on the Bishop method.For a specific example

the safety factor is analyzed in condition of different slope height and seismic acceleration amplitude

which is compared with the case with the uniform input.It is shown that the safety factor under the multi-point and multi-direction seismic motion is larger than the one under the single-point and single-direction seismic motion.It is revealed that when slope height is lower than 30m and seismic acceleration amplitude is less than 0.1g

the results of the safety factors of different seismic motion inputs are similar

but when slope height is higher than 30m and seismic acceleration amplitude is more than 0.1g

the maximal change rate is beyond 36%

when the input of multi-point and multi-direction seismic motion should be considered for slope stability evaluation.