Summary: A piecewise-linear Sprott system is proposed and its chaos mechanism is analyzed. According to the Shilnikov theorem, on the condition that the basic characteristics of heteroclinic orbit, Shilnikov inequality and eigenvalue equation are satisfied, by finding a heteroclinic orbit formed by three geometric invariant sets, namely the unstable manifold, heteroclinic point, and stable manifold, a set of real parameters in accordance with the condition of existence of heteroclinic orbit is obtained for this chaotic system. Thus, the existence of heteroclinic orbit is proved. Finally, according to this set of real parameters, the circuit design and experimental verification are carried out.