A　synthetic　method　of　multi-dimensional　and　multi-point　non-stationary　seismic　waves　(MMNSWs)　based　on　phase　difference　spectrum　is　proposed　to　simulate　the　non-stationarity　and　multi-dimensionality　of　real　ground　motions　in　hope　to　overcome　the　deficiencies　of　the　traditional　trigonometric　series　method,　such　as　the　arbitrariness　in　selection　of　the　envelope　function　and　loss　of　non-stationarity　feature　in　frequency　domain.　First,　the　traveling　wave　effect,　coherence　effect,　local　site　effect　and　multi-dimensional　property　of　ground　motions　are　modelled　using　the　random　field　theory.　Then,　the　phase　difference　spectrum　is　determined　and　used　to　characterize　the　non-stationarity　of　intensity　and　frequency　of　ground　motions.　Finally,　the　synthetic　non-stationary　ground　motions　are　applied　to　an　actual　bridge　for　seismic　analysis,　and　the　generated　dynamic　responses　are　compared　with　the　equivalent　response　spectrum　obtained　by　response　spectrum　method.　Results　show　that　the　MMNSWs　generated　based　on　phase　difference　spectrum　does　not　need　the　envelope　function　to　control　the　waveform　of　seismic　waves,　and　hence　can　exclude　the　arbitrariness　of　artificial　selection　of　the　intensity　envelope　function.　Since　it　has　taken　into　account　the　relevance　and　multidimensionality　of　seismic　ground　motions,　the　proposed　method　is　better　than　the　traditional　trigonometric　series　method　for　synthesis　of　ground　motions.　In　addition,　the　results　generated　by　the　proposed　method　are　basically　consistent　with　those　by　the　traditional　response　spectrum　method.　The　difference　between　the　values　of　shear　force　and　bending　moment　at　two　pier　bottoms,　calculated　by　the　response　spectrum　method,　is　in　the　range　of　10%　and　17%,　respectively,　while　the　difference　is　less　than　9%　and　12%,　respectively,　by　the　proposed　method.　©　2019,　Editorial　Department　of　Journal　of　Southwest　Jiaotong　University.　All　right　reserved.