Desktop-size robots are becoming commonly used in many fields such as caring, education and entertainment. But factors that affect human perception of desktop-size robots and their interaction are still unclear. The study examined the impact of robot behavior and appearance on the Robot Social Attributes Scale (RoSAS) during a virtual human-robot interaction study. The results showed that robots with human-like behavior were perceived more positively than those with random behavior, but the appearance of the robot did not have a significant impact on perception. The findings suggest that the design of humanlike behavior should be prioritized in future HRI studies and robot design. Real-world experiments are also recommended to verify the findings for the application of desktop-size robots in the healthcare field.