The design structure of the lap section between Shenzhong Link immersed tube tunnel foundation trench and 3 supporting channels is complicated.There are some problems such as poor integrity and continuity of section analysis，complicated analysis process and poor three-dimensional visualization effect in analyzing the excavation quality of base channel lap section by section method.To solve the above problems，three-dimensional foundation trench and channel design interface are established，and terrain collapse tool，three-dimensional chromatic aberration diagram tool，section analysis tool，overcut and undercut calculation tool are developed and customized for the second time.The three-dimensional model of base channel lap section is established by using three-dimensional design interface of foundation trench and channels and tools，and the quantitative three-dimensional visualization analysis of the excavation quality of base channel lap section is realized，including overall plane analysis of the overcut depth and undercut thickness by using three-dimension color block and numerical value of overcut and undercut，any vertical and horizontal section analysis of excavation quality，fast calculation of overcut and undercut engineering quantity in any local area.The results show that the overcut and undercut engineering quantity difference between the model and the section method is within ±1%，which meets the requirements of engineering application，and has the advantages of good integrity and continuity of the section analysis，fast calculation speed and high precision，and good three-dimensional visualization effect.It is especially suitable for the construction quality analysis of complex lap section with multiple superposition between the foundation trench and channel or the channel and channel.