Nowadays, most consumers prefer products with originality, fashion and innovation, and seek for quality and design. In addition, by the effects of the popularized knowledge of media products, the increasing educational level, the change of social concepts and the frequent interaction between human-beings, the demand of multimedia merchandises is raising and the expenditure is also increasing. The purpose of this study is to discuss the impact factors of purchase behavior by impulse buying and the relationship between the background knowledge to products and the purchase intention in multimedia expos in Kaohsiung area. After deleting invalid questionnaires, 501 of 550 research objects who were the consumers in the multimedia expo in Kaohsiung were taken into this study. The results which were made by research tools such as impulse buying scale, impulse buying behavior factors scale, product knowledge scale and purchase intention scale through statistic methods including reliability test, item analysis, factor analysis, descriptive statistics, independent samples t test, One-way ANOVA, Pearson's product-moment correlation and level regressions are as follows. (1) Significant differences can be seen in the catalogues of gender, marital status, age, educational level, occupation, average monthly wagers upon impose buying and the impact factors of behavior in the Multi Media Expo.(2) Consumers of various age or occupation have different knowledge level regarding the products. (3) Significant differences of purchase intentions between consumers in various educational levels in the multimedia expo. (4) Positive significant impacts of purchase intentions impacted by impulse buying especially in some promotion ways of advertisement, shopping situation and payment terms. (5) Significant influences of the impact between the consumers¡¦ shopping intentions and product knowledge. (6) Significant impacts in impulse buying personality to impulse shopping behavior and purchasing intention with positive interference between impulse shopping personality and purchasing intention. Negative impact occurs on shopping situation and purchasing intention regarding to impulse buying personality. (7) Significant interference impact on knowledge of products and shopping intention regarding to impulse buying personality. To conclude, except explaining and discussing the applications of the research result, the following suggestions were also mentioned to the exhibitors. (1) Combine marketing policies and product advertisement to raise the marketing performance. (2) Arrange better endorsements to attract the crowds. (3) Flexibly utilize quantitative promotions and main commodities to create a purchasing rush. (4) Properly plan the expo venue and improve the service quality to create situational stimuli. (5) Exercise various paying methods to improve the shopping intention of young people. (6) Make the best use of the consumers¡¦ product knowledge to improve shopping intention. (7) Utilize the interference impact of impulse shopping personality to raise the consumers¡¦ shopping intention. Moreover, some advices for future research were also mentioned.