Alexander II introduced reform for many reasons, the main being because of Russia’s overall industrial and economical backwardness. Alexander II wanted to improve the Russian empire as a whole, and reform was one of the ways in which he did this.
The most important reason was due to power. Alexander felt that Russia was economically lagging behind compared to Western Europe, and so wanted to catch up. Russia’s trade was suffering due to its lack of advanced machinery, and so Alexander wanted to try and industrialise. This included introducing more railways and modern technology, so the rest of Europe wouldn’t seem as much of a threat and competition.
Leading on from this, Russia’s humiliating defeat in the Crimean war showed Alexander the need to progress also in terms of military training and equipment. It was embarrassing that Russia, with a much larger force and population, had lost against the much smaller French and English troops. This made Alexander want to bring Russia forward and ensure the Serf Army, who were poorly paid and supplied, could compete against the armies of foreign threats.
The political structure in Russia was also a problem. It relied entirely on the nobles who were at the top end of society, with the control being tightened over them by Alexander’s father, Nicolas I. This was resulting in disloyalty, as income for the nobles was falling due to lack of trade. Peasants were also beginning to fight against control, and Alexander was keen to stop another revolt. Many people were beginning to disagree and criticise the autocratic rule, making Alexander’s reforms necessary to stay in power.
Lastly there is the simple reason of Alexander’s own character. Before ascending to the throne, Alexander travelled all of Russia and saw much of the poverty and problems for himself. He knew what he needed to change, and had a much more liberal attitude than his predecessor. He disapproved with how unfair Russia was, disagreeing with censorship and the harsh police state, so Alexander’s reforms as well as being necessary to stay in control may also have been a personal choice.
Overall, I think the main and most important reason for the changes Alexander made were due to his want to industrialise and modernise Russia. This would improve Russia as a whole, with trade, defence and the issue of communication, meaning it could at last achieve its aim of catching up with Western Europe.