I have been thinking of submitting a utility model in USA however i want to know what is the difference between utility model and utility patent and if the USPTO has utility model?
No, there is no concept of a Utility Model in the U.S. patent system. Many, many other places, Germany, China and Japan, for example, have utility model or petty patents that can have a lower bar for patentablity, a shorter term and often a lower assumption of validity than normal innovation patents. Unlike other places, the U.S. does have Design Patents for the protection of the ornamental aspects of a manufactured product. They have a shorter term than U.S. Utility Patents but are not really analogous to a petty patent since they cover the "look", rather the functioning or structure.
Utility Models are also usually confined to certain areas of technology - typically devices and excluding processes and systems.