The cycle model of a regenerative quantum heat engine working with many nonineracting harmonic oseillators is established. The cycle consists of two isothermol and two constant-frequency processes. The performance of cycle is investigated, based on the quantum master eqution and semigrop approach. The inherent regenerative losses in the two constant-frequency processes are calculated. The expressions of several important performance paramketers cases. Especially, the optimal performance of the cycle in htgh-temperature limit derived for several intersting cases. Especially, the optimal perfomance of the cycle in higt-temperature limit is discussed in detail. The maximum power output and the corresponding parameters are calculated. The optimal region of the efficiency and the optimal ranges of the temperatures of the working substance in the two isothermal processes are determined.