One of the problem that has occured in PT Pertamina MOR IV Semarang is the sales of Pertamax’s gasoline that losed from the sales of Pertalite’s gasoline. Perceived quality and brand image were among the factors that influence the purchase decision. The purposes of this research are to determine and analyze the influence of perceived quality (X1) and brand image (X2) to purchase decision of Pertamax’s gasoline (Y1) on motorcycles users in Tembalang’s district Semarang. The methods of data collection used in this research are observation, interview, literature study and questionnaires. The questionnaires used a simantic defferensial with 10 point scale and method of collecting the sample used is purposive sampling as many as 100 samples. The analysis tools used are test of validity, reliability test, normality test, heteroscedasticity test, multicollinerity test, linearity test, multiple linear regression, T test, F test, the coefficient of determination and multiple linear regression. Based on the calculations using SPSS version 16, the results of this research show that the regression equation Y= 4,280 + 0,284 X1 + 0,269 X2 + e. In addition, the F test result of 41.662 which is bigger than F table was 3,09. It can be concluded that the of perceived quality (X1) and brand image (X2) has a significant influence to purchase decision of Pertamax gasoline (Y1). The T test result the variables perceived quality (X1) and brand image (X2) is bigger than T table and has a significance less than level segnificance of 0,05. So, it can be concluded the perceived quality (X1) and brand image (X2) has a positive and significance influence to purchase decision of Pertamax gasoline (Y1). The most influence variable is perceived quality (X1) with the highest regression coefficient of 0,284.