With　the　flourishing　development　of　the　subway　construction,　more　and　more　attentions　are　paid　to　the　subway　tunnel　ventilation.　The　piston　wind　caused　by　the　running　trains　can　not　only　improve　the　tunnel　environment,　but　also　strengthen　the　power　of　the　tunnel　ventilation.　The　majority　of　the　current　researches　are　based　on　similar　experiments　or　CFD　simulations,　yet　most　of　which　lack　universality.　It　takes　long　time　to　finish　the　research　cycles　and　it　is　difficult　to　generalize　the　conclusions　based　on　these　researches.　This　paper　is　aimed　to　put　forward　a　universal　prediction　formula　to　estimate　the　ventilation　effect　of　piston　wind.　In　this　paper,　a　uniformly　accelerated　Bernoulli　theoretical　model　is　established　firstly,　which　is　validated　by　the　experimental　data　and　numerical　simulations.　Secondly,　a　passing　through　model　is　built　with　the　verified　theoretical　method　and　the　influence　of　the　key　parameters　on　the　ventilation　rate　are　analyzed.　Thirdly,　the　grey　correlation　analysis　is　conducted　to　study　each　influencing　factors,　meanwhile,　a　general　prediction　formula　on　the　ventilation　rate　is　proposed,　which　is　applicable　to　the　most　subway　tunnels　in　China.　Finally,　the　effects　of　the　trailing　distance　between　multi-trains　on　the　tunnel　ventilation　is　discussed.