This paper proposes the use of several ontological techniques to provide a semantic level solution for a search agent so that it can provide fast, precise, and stable search results in ubiquitous information environments. An ontological focused-crawler had been developed according to these techniques, which can benefit both user requests and domain semantics. Equipped with these techniques, the crawler can manifest the following interesting features: ontology-supported construction of Website models, Website models-supported Website model expansion, and Website models-supported Webpage retrieval.