The nematode Caenorhabditis elegans is an attractive model organism to study the behavioral plasticity for its simple system and ability to respond to diverse environmental stimuli, such as touch, smell, taste and temperature. Learning in C. elegans encompasses both non-associative learning and associative learning. Till now, themotaxis and chemotaxis are two major paradigms for associative learning and there are at least 6 forms of chemotaxis-mediated associative learning. Three research systems have also been explored to study the mechanism of learning choice in worms. This review will discuss the forms, research models, genetic and molecular regulation of learning and learning choice in C. elegans.