In　this　paper,　the　Lotka-Volterra　3-species　mutualism　models　with　diffusion　and　delay　effects　is　investigated.　A　simple　and　easily　verifiable　condition　is　given　to　ensure　the　global　asymptotic　stability　of　the　unique　positive　steady-state　solution　of　the　corresponding　steady-state　problem　in　a　bounded　domain　with　Neumann　boundary　condition.　Our　approach　to　the　problem　is　based　on　inequality　skill　and　the　method　of　the　upper　and　lower　solutions　for　a　more　general　reaction　diffusion　system.　Finally,　some　numerical　simulations　are　given　to　illustrate　our　results.　Copyright　(C)　2009　Chang-you　Wang　et　al.