The invention mainly discloses an equal-strength connecting joint and an equal-strength connecting method for components and plates made of different materials. The equal-strength connecting joint comprises a low-strength material component, a high-strength material component, transition sections and reinforcement plates. The components can be circular or box-shaped components, and internal reinforcement weld seams are welded via the transition sections, so that the circular components and cast steel can be connected with one another. The reinforcement plates are welded on the inner walls of the box-shaped components in advance, so that the components and the cast steel can be connected with one another in an equal-strength manner. The equal-strength connecting joint and the equal-strength connecting method have the advantages that steel materials which have different thicknesses and are made of the different materials can be connected with one another in an equal-strength manner, accordingly, the stress performance of the steel materials can be sufficiently played, and the safety of structures can be guaranteed; the equal-strength connecting joint is clear and definite in force transferring path, simple in structure, convenient to operate and high in efficiency.