The industry of mobile communication in Taiwan has recently become the fastest growing representative in the mobile communication related industries in the world. After several years of development, the industry has moved into the application development stage for 3rd generation (3G) technologies. Within the related services offered by 3G technologies, the most noticeable and the earliest one to set into promotion are video phone service. However, since 3G technologies become available in year 2005, the utilization of video phone service and its popularity keeps at slow growth. Scholars have pointed out that the consumers¡¦ perception of the products can have impact on their purchasing and using decisions. Further, some scholars also think that if the consumers believe the risk of change is high; their willingness to accept new services is lowered. Based on the above two factors, this research examines the current status on consumers¡¦ perception on 3G technologies and also investigates the interrelationships among consumers¡¦ perception of the cost of change and the utilization of 3G video phone service. After going through the literature on the subject, this research has categorized consumer knowledge into 4 types. In addition, the switching cost which arising from the change of voice service to 3G video phone service by consumers has also been included into the study. The conclusions and recommendations resulting from the investigation and analysis of current consumer knowledge and the switching cost are as follows: 1.Consumers¡¦ product existence knowledge on 3G video phone service and the persuasion knowledge does not have noticeable impact on its usage intention. However, the product attributes knowledge and the knowledge to purchase and usage have positive noticeable impact on its usage intention. 2.The switching cost for consumers to move from voice services to 3G video phone service has noticeable negative impact on its usage intention for 3G video phone service. 3.Consumers¡¦ persuasion knowledge for 3G video phone service has a negative relationship on the switching cost of change for 3G video phone service.