Trading in the stock of LTV Corp. of Dallas was suspended yesterday because the Securities and Exchange Commission is unhappy with the method the company uses to account for its inventory.

"We see the prospect of having to resrate earnings," as LTV spokesman said.

He said that the company requested the suspension of trading on the New York Exchange and that the SEC concurred. Because of a proposed merger between LTV and Lykes. Corp., trading in that company was also suspended.

The trading suspension extended to subsidiaries of both conglomerates, some of whose stock is traded separatedly from the parent's.

The SEC investigation, which was announced earlier, concerns the way LTV's wholly owned subsidiary, Jones & Laughlin Stel Corp., accounted for its inventories in 1975 and 1976.

"It now appeas that adjustments may be required," the company said in a statement. As a result, LTV predicted that "retained earnings of (its) companies would be adversely affected."

The trading suspension terminates on July 26, but the LTV's spokesman said: "It doesn't appear that we will ready restate within the suspension period."

An SEC official noted, however, that a recent Supreme Court decision bars trading suspensions for more than 10 trading days.