Time series analysis is used to estimate and predict behaviour of time dependent processes. In this project we have made use of two stochastic volatility models: Univariate Stochastic Volatility Model, and Multivariate Stochastic Volatility via Wishart Distribution. We estimated their parameters using combinations of MCMC methods, which are mainly Metropolis-Hastings Algorithm and Gibbs sampler. The work done gave us tools to estimate time dependent variance structure of the time series.