The invention relates to a carrier, and discloses a carrier frame mechanism. The carrier frame mechanism comprises a cross leg welding piece (1) which comprises two cross legs (11) and a cross leg transverse beam (12) used for connecting the two cross legs (11), and further comprises an ejection plate welding piece (2) and two stand column welding pieces (3); the bottom ends of the two stand column welding pieces (3) are fixed to the ends, close to a frame, of the two cross legs (11), and the top ends of the two stand column welding pieces (3) are connected through the ejection plate welding piece (2); and the stand column welding pieces (3) bend towards the extending-out ends of the cross legs (11) to be in arc shapes, and containing space for containing batteries is formed between the stand column welding pieces (3) and the cross leg transverse beam (12). According to the carrier frame mechanism, a surrounding plate connecting part of the carrier frame is improved, and therefore the number of machining steps can be decreased while the high bearing capacity is achieved, the battery containing space is reasonable, and the production cost is reduced.