Planning　is　important　in　the　process　of　engineering　reliability　and　growth.　Planning　models　and　the　related　curves　are　always　influenced　by　their　intrinsic　parameters.　However,　there　is　little　research　on　the　relationship　between　planning　models　and　their　inherent　parameters.　This　study　examines　the　relationships　between　the　planning　model　based　on　projection　methodology　(PM2　model)　and　its　four　inherent　parameters.　The　results　have　shown　that　all　four　parameters　have　a　significant　influence　on　the　reliability　growth-planning　curve.　Moreover,　they　reveal　that　some　parameters　have　minimum　limits.　By　prejudging　the　parameters　of　the　model,　the　risk　of　not　achieving　the　test　target　can　be　reduced.　This　study　will　provide　guidance　for　future　engineering　planning　and　management.