Registering the Oracle Spatial data as a layer of ArcSDE is a feasible way of converting data from Oracle Spatial to ArcGIS. It realizes the interoperation with Oracle Spatial data from the spatial data in other format. This paper analysis the register process using ArcSDE API or using sdelayer command and proposes an effective layer register method using SQL language for mass spatial data. Compared with the traditional layer register method, this new layer register method was improved in aspects of usability, security and efficiency.