系統路徑path的登錄檔項
!define PRODUCT_UNINST_ROOT_KEY "HKLM"     //HKEY_LOCAL_MACHINE的簡稱

!define PATH_KEY "SYSTEM\CurrentControlSet\Control\Session Manager\Environment" //path對應的HKLM下的登錄檔項

在安裝完成後欄位區新增

Var vPath //新加,自定義變數,用於接受原path中的變數值
Section -Post
  WriteUninstaller "$INSTDIR\uninst.exe"
  WriteRegStr ${PRODUCT_UNINST_ROOT_KEY} "${PRODUCT_UNINST_KEY}" "DisplayName" "$(^Name)"
  WriteRegStr ${PRODUCT_UNINST_ROOT_KEY} "${PRODUCT_UNINST_KEY}" "UninstallString" "$INSTDIR\uninst.exe"
  WriteRegStr ${PRODUCT_UNINST_ROOT_KEY} "${PRODUCT_UNINST_KEY}" "DisplayVersion" "${PRODUCT_VERSION}"
  WriteRegStr ${PRODUCT_UNINST_ROOT_KEY} "${PRODUCT_UNINST_KEY}" "URLInfoAbout" "${PRODUCT_WEB_SITE}"
  WriteRegStr ${PRODUCT_UNINST_ROOT_KEY} "${PRODUCT_UNINST_KEY}" "Publisher" "${PRODUCT_PUBLISHER}"

  ReadRegStr  $vPath ${PRODUCT_UNINST_ROOT_KEY} "${PATH_KEY}" "Path"   //取原值
  strcpy $vPath "$vPath+$INSTDIR"    //字串連線嘍
  WriteRegStr ${PRODUCT_UNINST_ROOT_KEY} "${PATH_KEY}" "Path" "$vPath"   //寫新值

SectionEnd

結束,謝謝賞光!