I lost my dji spark. I launch it with using only my phone as a controller and the time it take off. It went to ATTI mode and it continues to ascend and when it reach I think the maximum alt it told me to return home button. I did for how many time but there is no response from the aircraft and it continues to fly away. I am asking for your help if you can tell me if there is possible way to track it or find it. Please help me thank you.

Atti mode and phone only, my guess you have to calculate the wind direction and speed with the battery time of the Spark, to find it.
But you can upload your phone flight log to:
http://www.phantomhelp.com/logviewer/upload/

And post the link to that upload in here.
Some people in this forum are doing amazing jobs to get you as close as possible to where it might be

For now, open the dji go4 app and tap the three dashes at the upper right corner then tap (Find my drone) and check the location of your drone try to find there.

Sorry to hear your loss. You can use the DJI Go app to locate the drone if any GPS information is available in the log.

Elemar, sorry for your lost. I would recommend you contact our support and start a case: http://www.dji.com/support And you can provide the flight record to our support to locate the problem. Hope you can find you drone. Thanks for your support.