now i create model using ArcMap and want to use it in my android app
models are run as model tools from toolboxes in arctoolbox or even arccatalog or even within other models. I suspect that one of those requirements isn't being met. If you app doesn't permit access to these, then I suspect it isn't possible to do so in the way you want
Running a model tool—Help | ArcGIS for Desktop
Running custom (model or script) tools in the background—Help | ArcGIS for Desktop
Integrating a model within a model—Help | ArcGIS for Desktop
Sounds like you have a model that is basically some geoprocessing steps. You could publish your model as a geoprocessing service and then consume the service in you app.
Retrieving data ...