Abstract: A hybrid dual-infeed high voltage direct current（HVDC） system contains line commutated converter based HVDC（LCC-HVDC） and voltage source converter based HVDC（VSC-HVDC） which has electrical coupling between terminal locations. VSC-HVDC system has the characteristics of independently adjustable active and reactive power. The power transmission capability of LCC-HVDC can be improved by adjusting active and reactive power output of VSC-HVDC system at the same receiving end. Based on the mathematical and simulation model of hybrid dual-infeed HVDC system, the power transmission capability of hybrid HVDC system with different strength of the receiving end grid is analyzed by proposing a numerical solution to find the critical point of system stability. According to the analysis result of the impact of adjusting active and reactive power output of VSC-HVDC system on the transmission capacity of LCC-HVDC system, a maximum transmission power control method based on fixed virtual point voltage control is proposed, which can automatically adjust the power parameters so as to control the transmission power of hybrid HVDC system to the upper limit when the strength of the receiving end grid changes.