Stock market is an important part of economy of a country. Measuring stock market volatility is an vital issue in finance. There are various models to evaluate volatility. The daily return series shows that there is a variation of closing prices of AB bank. The data of AB bank includes daily closing prices from 01-01-2015 to 05-10-2017 from Dhaka Stock Exchange (DSE) library to forecast phenomena of stock market volatility. We use GARCH models to assess the volatility of stocks from banking sector and find that GARCH (1,1) model is best for measuring volatility of the stocks of AB bank. Once if we measure the volatility then it is possible to make best prediction when to buy and when to sell a stock.