In a major restructuring move, Santa Fe Southern Pacific Corp. said yesterday that it plans to buy back up to 60 million shares, or 38 percent, of its stock.

To help finance the purchase, the company said it will offer up to 20 percent of its wholly owned Santa Fe Energy Co. to the public by the end of the year. The company said the rest of the buyback would be financed by previously announced divestitures and additional debt.

The railroad and natural resource holding company, which earlier this year was, in effect, ordered by the Interstate Commerce Commission to divest one of its railroads, also said it will create a real estate investment trust with about $300 million of its income-producing property and distribute the shares to stockholders.

In New York Stock Exchange trading yesterday, Santa Fe Southern Pacific shares rose 50 cents, to $56.75. While the company said the timing of its stock buyback would be determined by "market conditions, the progress of the divestiture plan and other investment alternatives," repurchasing 60 million shares would cost about $3.4 billion at current prices.

"When completed, these actions will result in a more focused and leaner company utilizing somewhat greater leverage," said Robert D. Krebs, chief executive officer of Santa Fe.

The moves come on the heels of a plan filed with the ICC earlier this month to divest Southern Pacific Transportation Co. The agency had denied, on antitrust grounds, the company's application to merge the Southern Pacific with the Atchison Topeka & Santa Fe.

Last June, the company said it was selling most of its income-producing timber, pipeline and leasing companies.

"It will be a lot smaller company when they get done," said Burton M. Strauss, a rail analyst with E.F. Hutton Inc.

Several analysts contacted yesterday were not willing to estimate the value of the various assets Santa Fe now has up for sale.

Several bidders have emerged for the Southern Pacific, including the Railway Labor Executives Association, a 17-union consortium that wants to create an employe buyout, and Kansas City Southern Industries Inc.

According to Santa Fe, its energy company produces 54,600 barrels of crude oil and 90 million cubic feet of natural gas daily in 14 states, the Gulf of Mexico and off California. At the end of last year, the company had 124 million barrels of proven oil reserves and 191 billion cubic feet of natural gas reserves. The company has since added the assets of Petro Lewis Corp., a California concern.

The company said the property being transferred into the real estate investment trust includes a mixture of industrial and commercial property, with a considerable portion located in California.

Santa Fe has been under considerable pressure to raise its stock price, which earlier this year was as low as $33 a share.