Nonstationarity　is　an　important　characteristic　to　represent　the　randomness　and　the　variability　of　engineering　signal,　and　its　quantification　and　evaluation　is　the　effective　basis　for　signal　analysis　and　pattern　recognition.　The　typical　calculation　algorithms　of　the　global　non-stationary　and　local　non-stationary　are　demonstrated　and　compared.　Based　on　moving　statistical　analysis,　the　concept　and　algorithms　of　moving　mean　value,　moving　variance　and　moving　variation　coefficient　are　proposed,　in　order　to　fully　characterize　the　varying　details　in　time　domain　and　the　diversity　of　different　signals.　By　the　nonstationarity　analysis　of　different　mechanical　fault　signals　and　ECG　signals,　the　evaluation　capability　and　applicability　of　different　algorithms　are　analyzed　and　compared.　The　results　indicate　that　in　the　evaluation　method　of　nonstationarity,　the　moving　statistics　method　has　outstanding　theoretical　foundation,　precision　and　stability.　©　2018,　Editorial　Department　of　JVMD.　All　right　reserved.