Inflation occurring in Indonesia tends to not be able to cover investment in the form of savings. The capital market in Indonesia is currently promoting investment in shares with the slogan" let's save shares", which at this time the returns continue to improve. This research was conducted to identify the characteristics of stock investors in the Indonesian stock exchange, analyze the decision making process of stock investors to choose stocks in the Indonesian stock exchange and find out what factors influence investors in investing in the capital market and to be an additional understanding in capital market subjects. This research was conducted at the faculty of economics UNIMED. In evaluating alternatives in making purchases, it turns out stock is the main choice with the main consideration being the profit potential. In determining the purchase decision all respondents have planned well and themselves have the most influence with the decision making time ranging from 2-7 days. Post-purchase behavior respondents were satisfied with their decision and the waiting time to get benefits ranged from 3-4 weeks. This research shows, there are 4 factors that influence investors in buying and selling shares on the Indonesia Stock Exchange, namely information factors, preferred stock factors, market activity factors and risk limiting factors. The most influential dominant factor is the information factor of 46.52 percent.