We　study　group　formation　in　the　spatial　public　goods　game　with　continuous　strategies.　An　active　group　will　become　inactive　with　high　(low)　probability　if　the　collective　contribution　is　below　(above)　a　threshold　value.　Meanwhile,　an　inactive　group　recovers　to　be　active　with　some　probability.　We　have　found　that　the　cooperation　level　and　the　average　payoff　of　players　are　maximized　at　moderate　values　of　the　threshold　and　the　recovery　rate.　Spatial　distributions　of　strategies　and　active　groups　are　plotted　to　understand　the　evolution　of　cooperation.　2018　Elsevier　B.V.　All　rights　reserved.