To solve the problem of inaccurate acquisition of component reliability parameters in practical HVDC transmission projects, a solution model of HVDC system component reliability parameters based on interval algorithm is proposed. Firstly, the reliability evaluation model of the HVDC subsystem is established by using an analytic method, and the reliability index of the HVDC system is obtained by using the time series Monte Carlo method. Secondly, the analytical expression of the reliability index of the HVDC system on component reliability parameters is derived by using the full probability formula. Then, the reliability index of the components is established, and the interval algorithm for combining interval bisection and Krawczyk-Hansen is used to solve the reliability parameters of main components. Finally, a double twelve pulse HVDC system is used to verify the correctness and effectiveness of the proposed model and method. The results of the case study show that the model and method can find the exact interval solution of the component reliability parameters in a large initial parameter range.