In actual quantum computing, qubits and quantum operations exhibit different quality characteristics, which affect the fidelity of quantum computing results. While among the quality characteristics, the error rate of controlled-NOT (CNOT) quantum gate occupies a major position. This research proposes a quantum circuit conversion method that not only satisfies the connectivity constraints but also improves fidelity. The method first finds out the qubit moving path through Floyd algorithm, and constructs a heuristic function based on the success rate of one or more two-qubit gates on the path, then select the high-fidelity switching mode in this circuit. Multiple benchmark experiments show that compared with SabreSwap and StochasticSwap algorithms in IBM Qiskit toolkit, the proposed method improves the quantum line fidelity by 39.29% and 36.06% respectively.