During design procedure, under-constrained problem is met usually, for each type of under-constrained problem, this paper generalizes associated solution method, which can be used in CAD programming.

• 在实际设计的过程中，欠约束问题是经常遇到的，对每一种类型欠约束问题的求解，本文归纳出了对应的求解方法，可以在程序中加以应用。