can i complete my diploma in computer science after 10th std and after complete my btech can i apply in mtech for abroad studies
Yes, you can pursue, perhaps the Course abroad is M.Eng/MS not MTech in most of the Countries. However, mostly Postgraduate Courses are Self Funded and youre not given any sort of Loan, Scholarship or Funding, unlike PhD.
What I would advise you is after Diploma and Completing BTech either as Lateral Degree or Associate Degree, you should target MTech in Computer Science from some of the Higher Technical Institutes in India like Top IITs, NITs, IISc Bangalore and so on. You have excellent faculty and placements besides not having to worry about the Tuition fee, which is very less. You even get the M.Tech Stipend, which is very useful in student days.
After MTech, and a strong work experience, if interested you may pursue a MBA/MS/PhD in a relevant discipline in some of the Top Universities Abroad and take steps towards settling there with a Job.