The invention provides an audio synchronous playing method and device, video playing equipment and a readable storage medium, and relates to the field of audio playing. The method comprises the following steps: obtaining a first recording signal and a second recording signal when a built-in sound box and an external sound box respectively play a plurality of calibration sound signals in sequence,determining a sound pressure association ratio of the external sound box to the built-in sound box, and further determining the sound pressure of the built-in sound box based on the sound pressure association ratio and a first corresponding relationship between the sound pressure level and the volume value of the built-in sound box; determining a second corresponding relationship between the soundpressure level and the volume value of the external sound box; and then, performing audio playing time synchronization on the built-in and external sound boxes, and respectively performing sound pressure level adjustment on the built-in sound box and the external sound box according to the target volume of the to-be-played audio frame and the first corresponding relationship or the second corresponding relationship, so as to enable the built-in and external sound boxes to have the same audio playing opportunity and audio playing loudness for the audio frame to be played. Therefore, audio synchronous playing of the internal and external loudspeaker boxes is achieved, and the audio-visual experience of a user is improved.