Abstract: Functional semantic based Web service filter is a useful method to decrease the computation of service discovery．According to the problem that current semantic-based services description languages can not support service functional description,this paper firstly defined a functional based Web service semantic description model and created a domain oriented functional ontology．Based on this,a service description method was raised and a realize method based on OWL-S was expressed clearly．Finally a pre-filter method was raised．The pre-filter method can support the service discovery based on functional semantic,filter out unrelated services,decrease the computation of accurate service match and increase the matching efficiency.

Key words: Functional semantic,Service description,Domain ontology,Pre-filter