How to make AssetBundle ref: http://qiita.com/TomoakiNagahara/items/e48144b7778d9fb4213e

ExportAssetBundles.cs

using UnityEngine;
using UnityEditor;
using System.Collections;
using System.IO;

public class ExportAssetBundles : MonoBehaviour
{
    [MenuItem("Assets/Unity 5.x Build AssetBundle")]
    static void ExportResource_Unity5()
    {
        Debug.Log("Target=" + EditorUserBuildSettings.activeBuildTarget.ToString());

        // Folder name is PlatForm name
        string OutPutPath = Application.streamingAssetsPath + "/" + EditorUserBuildSettings.activeBuildTarget.ToString();

        if (Directory.Exists(OutPutPath) == false )
        {
            Directory.CreateDirectory(OutPutPath);
        }

        // Build AssetBundle at platform manifest.
        BuildPipeline.BuildAssetBundles(OutPutPath, 0, EditorUserBuildSettings.activeBuildTarget);
        Debug.Log("ComPress End");
    }
}