Nowadays the economic is growing very fast and the vehicle industry is thenumber one of industry in Thailand. The number of purchasing car in Thailand isincrease very fast and this year the government have policy that support for citizen who want to buy a new car for first time. The problem is when the customer bought the car already, which strategy that can make the customer come back to use the aftersales service because nowadays have many competitors such as aftersales service for other brand, garage etc., because Arthur D. Little (2008) and Prof.dr. H.G. Schmidt (2011) founded the after-sales service cam make more profit in many businesses. The issue is how to get the customer come back to aftersales service and increase the number ofcustomer loyalty. The purpose of this study is to identify the effect of commitment, trust, competence, communication, conflict handling on relationship quality, customer satisfaction and customer loyalty. Structural Equation Model (SEM) statistics technique was used to f ind out theanswer of the objectives in this study. 433 customers answered the questionnaires. The goodness of fit statistics revealed the fit of the model. The chi-square value was 1.94 with the degree of freedom (p=0.3785). Goodness of Fit Index (GFI) was equal to 0.99, Adjusted Goodness of Fit Index (AGFI) was equal to 0.98 and Root Mean Square Residual (RMR) was 0.0016 which support to this model. The result of SEM analysis demonstrates that the customer loyalty have 2 main variable that have effect to; customer satisfaction and relation quality. The result found customer satisfaction have positive effect to customer loyalty at 0.67 and relationship quality have positive effect to customer loyalty at 0.33. The variable that measure the customer satisfaction have competence, communication and conflict handling. This research founded competence have positive effect to customer satisfaction at 0.47, communication have positive effect to customer satisfaction at 0.24 and conflict handling have positive effect to customer satisfaction at 0.20. Relationship quality have 2 variables to measure are commitment and trust. This research founded that commitment have positive effect to relationship quality at 0.57 and trust have positive effect to relationship quality at 0.39. The implication of this study exposes that the effect that have the higher weight to customer loyalty and how to increase the number of customer loyalty. They should concentrate on the staff that comes to serve the customer first. Refer the result they should know what the customer need when they come the aftersales service and the customer satisfaction is the most important to customer loyalty, if they need to increase the satisfy of customer they should be focus on competence of staff and following with good communication and conflict handling skill. The training become the most important that aftersales service cannot be neglect.