In the reign of Emperor the Second of the Qin Dynasty (221-207 B.C.), the prime minister Zhao Gao, obsessed with ambitions, was planning to usurp the throne day and night. But he did not know how many of the ministers in the court were allowed to be ordered about by him and how many of them were his opponents. So he thought out a way to test how high his prestige among the ministers was and also to find out who dared to oppose him.
One day when court was held, Zhao Gao let someone bring a stag to the court and, with a broad smile on his face, he said to Emperor the Second of the Qin Dynasty:"Your Majesty, here is a fine horse I'm presenting to you." Looking at the animal, Emperor the Second thought that it was obviously a stag and that it couldn't be a horse. So he said smilingly to Zhao Gao:"Mister Prime Minister, you are wrong. This is a stay. Why do you say it is a horse?" Remaining calm, Zhao Gao said:"Will your Majesty please see more clearly? This really is a horse that covers a thousand li a day." Filled with suspicion, Emperor the Second looked at the stag again and said:"How can the antlers be grown on the head of a horse?" Turning around and pointing his finger at the ministers, Zhao Gao said in a loud voice:"if our Majesty do not believe me, you can ask the ministers."
The nonsense of Zhao Gao made the ministers totally at a lose, and they whispered to themselves: What tricks was Zhao Gao playing? Was it not obvious whether it was a stag or a horse? But when they saw the sinister smile on Zhao Gao's face and his two rolling eyes which were gazing at each of them, they suddenly understood his evil intentions.
Some of the ministers who were timid and yet had a sense of right eousness did not dare to say anything, because to tell lies would make their conscience uneasy and to tell the truth would mean that they would be persecuted by Zhao Gao later. Some ministers with a sense of justice persisted that it was a stag and not a horse. There were still some crafty and fawning ministers who followed Zhao Gao closely in ordinary times. They immediately voiced their support to Zhao Gao, saying to the emperor:"This really in a horse that covers a thousand li a day."
After the event, Zhao Gao punished by various means those ministers with a sense of justice who were not obedient to him, even with whole families of some of those ministers executed.
This story appears in "The Life of the First Emperor of the Qin Dynasty" in The Historical Records written by Sima Qian. From this story people have derived the set phrase "calling a stag a horse" to mean deliberately misrepresenting some thing and misleading the public.
秦二世時，丞相趙高野心勃勃，日夜盤算著要篡奪皇位。可朝中大臣有多少人能聽他擺布，有多少人反對他，他心中沒底。于是，他想了一個辦法，準備試一試自己的威信，同時也可以摸清敢于反對他的人。
一天上朝時，趙高讓人牽來一只鹿，滿臉堆笑地對秦二世說：“陛下，我獻給您一匹好馬?！鼻囟酪豢?，心想：這哪里是馬，這分明是一只鹿嘛！便笑著對趙高說：“丞相搞錯了，這里一只鹿，你怎么說是馬呢？”趙高面不改色心不跳地說：“請陛下看清楚，這的確是一匹千里馬?！鼻囟烙挚戳丝茨侵宦梗瑢⑿艑⒁傻卣f：“馬的頭上怎么會長角呢？”趙高一轉(zhuǎn)身，用手指著眾大臣，大聲說：“陛下如果不信我的話，可以問問眾位大臣。”
大臣們都被趙高的一派胡言搞得不知所措，私下里嘀咕：這個趙高搞什么名堂？是鹿是馬這不是明擺著嗎！當看到趙高臉上露出陰險的笑容，兩只眼睛骨碌碌輪流地盯著趙高臉上露出陰險的笑容，兩只眼睛骨碌碌輪流地盯著每個人的時候，大臣們忽然明白了他的用意。
一些膽小又有正義感的人都低下頭，不敢說話，因為說假話，對不起自己的良心，說真話又怕日后被趙高所害。有些正直的人，堅持認為是說明書而不是馬。還有一些平時就緊跟趙高的奸佞之人立刻表示擁護趙高的說法，對皇上說，“這確是一匹千里馬！”
事后，趙高通過各種手段把那些不順從自己的正直大臣紛紛治罪，甚至滿門抄斬。
故事出自《史記·秦始皇本紀》。成語“指鹿為馬”比喻故意顛倒是非，混淆黑白。??