Net income in January-June came to 334.8 million yuan ($52.42 million), compared with 1.4 billion yuan a year earlier, according to a stock exchange filing.
Encouraged to expand after Beijing fired up a $644 billion stimulus package in 2008, Chinese heavy equipment makers are stuck with a glut of unsold equipment, factories they do not need and tumbling earnings.
Even the $40 billion infrastructure investments pledged by the government across central, west and south Asia to as far as Greece, Russia and Oman were not a quick fix for their troubles.
Sany's shares closed up 7.8 percent on Friday, leading a 4.9 percent gain of the benchmark index.