How Can I Send Data Android To .Net Database .

Create a webservice in your .net side in a .asmx file.
Write some function inside that webservice like below:

[webmethod]
public void InsertIMEI(string IMEI)
{
 //do your insert part here
}

then from your android page supply a string IMEI value of the respective device by calling this service method,and you done.

Use kSOAP library to consume the webservices from android side.

you will find details about kSOAP library and way to consume webservices in below link..
http://code.tutsplus.com/tutorials/consuming-web-services-with-ksoap--mobile-21242[^]