在数学中，构造性证明是证明方法的一种，通过直接或间接构造出具有命题所要求的性质的实例来完成证明。与构造性证明相对的概念是非构造性证明（有时也称为存在性证明或纯粹存在性证明）。后者只证明满足命题要求的物体存在，而不提供具体的实例或构造这样的实例的方法。

In mathematics, a constructive proof is a method of proof that demonstrates the existence of a mathematical object by creating or providing a method for creating the object. This is in contrast to a non-constructive proof (also known as an existence proof or pure existence theorem) which proves the existence of a particular kind of object without providing an example.