A cart has a sunshade connecting device that includes a standpipe upper joint with a standpipe mounting hole that receives a standpipe of the cart and a plug-in mounting hole that receives a sunshade seat. A mounting groove is positioned above the plug-in mounting hole. A quick release button clamp is arranged in the mounting groove and adapted to engage a fixing groove on the sunshade seat. A plug head mechanism is configured for pushing the sunshade seat upward out of the plug-in mounting hole. The sunshade seat may be plugged into the plug-in mounting hole with the quick release button engaged with the fixing groove to fix the sunshade seat. When the sunshade needs to be removed, the quick release button may be pressed and disengaged from the fixing groove of the sunshade seat. The plug head mechanism may then eject the sunshade seat from the plug-in mounting hole.