A data acquisition system based on a CAN bus belongs to the technical field of data acquisition. The data acquisition system aims at solving the problems of single type data collected by the prior data acquisition system and low operational reliability. The data acquisition system comprises a data acquisition layer, a data transmission layer and a data processing layer, wherein the data acquisition layer comprises a serial port data acquisition group, an analog quantity data acquisition group and a digital quantity data acquisition group which respectively collect the corresponding type of data and transmit the data to the data processing layer through the data transmission layer for processing; the data transmission layer consists of a CAN interface car and an interface chip; and a data communication link established by utilizing the CAN bus protocol transports the data collected by the data acquisition layer to the data processing layer which is a host of a voyage data recorder and receives and processes the data collected by the data collecting layer. The acquisition of serial data, analog quantity data and digital quantity data simultaneously can be performed by the data acquisition system independently; and the operational reliability is high.