The objectives of this research were to: 1) study personal factors marketing mix factors level and service decision behavior, and 2) study relationship between consumer characteristics factors level how they affect consumer behavior in the decision to use services of commercial banks in Khon Kaen Municipality. There were 400 samples used quota sampling and purposive sampling. Questionnaires were used for collecting the data. The statistics used in the study including frequency , percentage , mean (x ̅) , standard deviation (SD) , Independent Sample t-test, f-test and chi-square. The research found that. 1. Most consumers were female at the age between 31-40 years, held bachelor degree, worked at private companies, had average monthly income 20,001-30,000 bath, selected to use Kasikorn Bank service, preferred to use the bank counter for deposit and withdrawal services, the reason to use the commercial bank was the short distance from house and office, and use the banking service 3-4 times per month between 11.31-14.30 hours. 2. The overall marketing mix factors 7P's was at the highest level (x ̅ = 4.16) the people is at the highest level ที่สุด (x ̅ = 4.58) followed by the physical (x ̅ = 4.38) Process (x ̅ = 4.25) Product (x ̅ = 3.96) (x ̅ = 4.21) price (x ̅ = 3.95) the place or Chanel (x ̅ = 3.94) and promotion (x ̅ = 3.71) respectively. 3. Personal factors of gender, age, education level, occupation, income and banking services. Relationship with decision making behavior of commercial banks. Significant at the 0.05 level, and Personal factors vary by educational level and banks that use the service. Marketing mix was significantly different at 0.05 level.