pls,suggest me for corporate valuation method

You look around online for a securities analysts report. That is what they do for a living :) "Step by Step Business Analysis and Valuation, Using Financial Statements to Value any Business by Krishna Palepu, Victor Bernard and Paul Healy. I got my copy a while ago for $24.95 on Amazon.com. It is out of print and used copies start around $80. Looks like it is time to sell high. Get this at a library. The more you take finance apart the fuzzier it gets. The state of the world economy. The state of the country economy. The state of the industry. Projected inflation. Projected earnings. Face it, you are predicting the future. There are several methods. I personally like discounted cash flows (future earnings). Have fun!

Along with the above, "Security Analysis" by Graham, Dodd, & Cottle. The SEC website is a great source for corporate financial statements, in full. By going to corporate websites, you can listen in on coference calls and presentations. Buffet recommends learning all you can about accounting. Good luck, have fun, and profit.