A pulse modulation circuit with a high-frequency-limiting function, including a comparator, an RS trigger, a switching triode, a NAND gate, a NOR gate, and a charging capacitor. A capacitor charging time is controlled by adjusting a bias current IB1, a bias current IB2, a reference voltage V1, and a reference voltage V2 or adjusting values of capacitors C1 and C2. In this way, a highest output frequency of a pulse generator is limited, so as to reduce hardware system overheads.