The charge management system for test masses in space inertial sensors requires high-frequency pulsed driving of ultraviolet (UV) LEDs to control surface charge, yet traditional Howland current sources face critical bottlenecks—output impedance attenuation, limited bandwidth and instability under high-frequency square-wave driving—hindering precise charge control and space missions. To address this, we propose a dual-buffer load-included Howland (DB-LIH) current source. By designing a dual-buffer Howland (DBH) circuit with dual voltage followers isolating feedback paths and a 0.01%-matched precision resistor network LT5400 suppressing mismatch effects, the DB-LIH architecture incorporates the load into the feedback loop to block stray capacitance currents. Simulations show the output current flatness factor (FF) induced by stray capacitance drops from 18% (DBH) to 0.03% (DB-LIH), with bandwidth reaching 1 MHz. Experimental results show that output accuracy better than 4.27% (0.05~50 mA range), resolution deviation less than 1.67% and 1 mHz~1 Hz relative amplitude stability of 0.01 Hz-1/2. This work resolves high-frequency constant-current precision and stability issues, meeting stringent requirements for space gravitational wave detection.