The status of probabilistic analysis and risk assessments for transient stability is reviewed， in terms of stochastic variables， probabilistic models， probabilistic algorithms， deterministic transient stability consequence assessments of a specifically scenario and other aspects. The principle， advantages and disadvantages of various assessment methods are summarized， and the techniques capable of decreasing computation burden are discussed. The development direction of probability and risk assessments for transient stability is also explored. It is pointed out that using sensitivity analysis to reduce the number of simulation cases will considerably decrease computational burden. It is also proposed to use the optimum control cost to reflect economic loss due to the system instability， which means using controllable outages to replace the uncontrolled outages and makes risk analysis practical.