Recent years, potassium-ion battery (PIB) is becoming a popular alternative to lithium-ion batteries due to their low-cost and abundant potassium resources. Potassium manganese hexacyanoferrate (K-MnHCF) has been considered as a promising cathode material for potassium-ion batteries on account of their high potential and capacity, but also suffers from the poor cyclic performance. Herein, a synergistic strategy combining the defects-reducing of K-MnHCF together with the electrode/electrolyte interface-stabilizing is developed to boost the electrochemical potassium-ions storage performance. By adjusting the co-precipitation process, K-MnHCF displays the regular cubic particle with the size of 100 - 150 nm, exhibiting the reversable capacity of 95 mAh g^-1 in KPF₆ electrolyte system. Moreover, stabilizing the interface between K-MnHCF cathode material and electrolyte is further applied to enhance the cycling stability and coulombic efficiency of K-MnHCF cathode, by reducing the side reactions at the interface in high concentration KFSI electrolyte system. Here, we will discuss how to design the cathode materials and electrode/electrolyte interface to enhance the potassium storage performance. These works give some suggestions about the synergistic regulation of low-defects manganese hexacyanoferrates with stable electrode/electrolyte interface for boosting the electrochemical performance of PIBs.