Very fine guest particles were partially coated onto the surfaces of cohesive particles using a patent-pending dry particle coating method involving shear force. It was observed that partial coating on the surfaces could significantly reduce the cohesiveness and hence enhance the flowability of cohesive host particles. Based on different contacting status of the guest particles in relation to the host particles, two contact models were proposed. Inter-particle forces based on these models were employed to discuss the possible roles of the guest particles, partially coated on the host particle surfaces, in reducing the cohesiveness of the host particles.