The present disclosure provides a method for playing an MP4 online, an electronic device, and a computer readable storage medium. The present disclosure relates to the technical fields of artificial intelligence, and further relates to the technical fields of media cloud. A specific embodiment of the method includes: acquiring a total size of a target MP4 file, and determining a target data length based on the total size and a preset proportion, where the preset proportion is determined based on a proportion of MOOV data to a complete MP4 file; acquiring header data having the target data length from a header of the MP4 file, and acquiring trailer data having the target data length from a trailer of the MP4 file; and playing the target MP4 file online based on actual MOOV data extracted from the header data or the trailer data.