Disclosed are an optical burst transport network (OBTN) time slot length adjustment method, device and node, the method comprising: during OBTN initialization, measuring the circumference of a data channel, and calculating the OB time slot length according to the measurement result; and during the normal operation of an OBTN, conducting real-time detection on the circumference variation of the OBTN data channel, comparing a variation value with a preset threshold, and correspondingly processing the OB time slot length according to the comparison result. The device is disposed on the node and comprises: a circumference measurement module of the data channel, a time slot length calculation and adjustment module, and a detection module, the circumference measurement module being configured to measure the circumference of the data channel, the time slot length calculation and adjustment module being configured to calculate the OB time slot length according to the circumference measurement result, and correspondingly process the OB time slot length according to the comparison result of the detection module, and the detection module being configured to compare the circumference variation value with the preset threshold.