Abstract: An extension ladder assembly having an anti-slipping mechanism is provided. The extension ladder includes a master ladder, a slave ladder, a pulley, a locking mechanism, the antislipping mechanism and adjustable ladder feet. The master ladder and the slave ladder are each composed of two posts and several rungs. The master ladder and the slave ladder are each composed of two posts and several rungs. The master ladder is slightly wider than the slave ladder. The anti-slipping mechanism prevents the slave ladder from being tripped and slid down, thereby safeguarding the safety of a user of the ladder. The pulley and the locking mechanism make the extension ladder suitable for various height requirements on work sites. The adjustable ladder feet make the extension ladder stand firm and secure by fine and minor adjustment of angles to accommodate different surface or ground conditions the ladder is placed upon.