The judgment of sequence surface is an essential and important parts in research of sequence Stratigraphy. Geophysical logging curve reflect the sedimetal change, and the value of geophysical logging curve is a function of depth. The first rank derivative is a reflection of curve change and its rate, at certain range, if the sign of the first rank derivative has changed, the logging value of the correspondence depth point means maximum （minimum） in this range; the second rank derivative is the knaggy property reflection of curve, at certain range, if the sign of the second rank derivative has changed, the correspondence depth point represent the inflexion of geophysical logging curve, it＇s also a turning point of the reflection of knaggy change property of the curve, it is the interface of stratum. At the base of those characteristics, this article put forward a new principal and method to judge interface of stratum and sequence, and also gives the sequence stratigraphy analysis resolute of wall Da28 Tengge＇er member, Baiyingchagan depression after doing research work in analysis of sedimentary cycle in different lever, stratum accumulation, specialty of cycle characteristic change to sediment thickness, and base-lever cycle in different lever.