McDonald's won labor peace for its first restaurant in Mexico today, reaching an agreement in which its employes will join a union but will continue to work part-time, company representatives and government labor officials said.

The powerful Mexican restaurant workers union that has occupied and shut down the McDonald's here since Dec. 3 agreed to withdraw its pickets even though it will not be the union that represents the outlet's workers, according to the agreement signed this afternoon.

"They have lifted the strike," government labor official Emilio Ruz Avila said.

The union lost its fight to force McDonald's to adopt the Mexican restaurant industry practice of hiring only full-time workers. But it apparently was satisfied that McDonald's agreed to hire union labor.

The agreement was reached at Mexico City's Labor Arbitration Board. Government labor officials urged the company and union to reach a deal before a vote scheduled for this afternoon. The restaurant workers union was expected to lose an election to select a bargaining representative for McDonald's 210 employes. The election was canceled after another union stepped in to represent the workers, Ruz Avila said.

The restaurant union occupied the McDonald's outlet's grounds without the visible support of the workers there. The company had said that it was willing to accept a union but only if the workers endorsed it.

The pay and hours for the McDonald's workers will be the same as before the takeover, Ruz Avila and McDonald's lawyer Jorge de Regil said. The only difference is that the McDonald's workers will join the new union, they said.